Particularities and construction requirements of powder coatings

The particularity and construction requirements of powder coating powder coating is a new type of solvent-free 100% solid powder coating Two kinds of thermoplastic powder coating and thermosetting powder coating are mixed by special resin filler curing agent and other additives in a certain proportion and then passed They are prepared by the processes of hot extrusion and crushing and sieving They are stored stably at room temperature After electrostatic spraying or fluidized bed soaking, they are heated, baked, melted and solidified to form a smooth and bright permanent film to achieve the purpose of decoration and corrosion prevention 1 The product does not contain toxic, solvent-free and volatile toxic substances, so it is free of poisoning, fire and other three Waste discharge and other public hazards fully meet the requirements of the national environmental protection law 2 The utilization rate of raw materials is higher than that of over sprayed powder 3 After pretreatment of coated materials, one-time construction can get enough thickness of coating without primer 4 The coating has dense adhesion, good impact strength and toughness, high corner coverage, excellent chemical resistance and electrical insulation properties 5 The powder coating is safe and convenient for storage and transportation The construction process and requirements of powder spraying are that the principle of high-voltage electrostatic corona field is used in powder electrostatic spraying The metal guide sign at the head of the spray gun is connected with the high-voltage negative pole, and the sprayed workpiece is grounded to form a positive pole, so that a strong electrostatic field is formed between the spray gun and the workpiece as the compressed air for carrying gas When the powder coating is sent from the powder supply barrel to the guide rod of the spray gun through the powder pipe, the corona discharge generated by the guide rod connected with the high-voltage negative pole produces a dense negative charge near it, which makes the powder Under the double action of electrostatic force and carrier gas, the powder flies evenly to the surface of the grounded workpiece to form a thick, thin and uniform powder layer, which is then heated and solidified to become a durable coating construction process, i.e pretreatment, drying, water removal, spraying, inspection, baking, inspection, finished product construction requirements, general powder spraying construction It is required that (1) in order to give full play to the characteristics of powder coating and extend the service life of the coating film, the surface of the coating materials shall be strictly pretreated (2) the coating materials shall be completely grounded to increase the spray efficiency of powder coating (3) the coating materials with large surface defects shall be coated with conductive putty to ensure the flatness and smoothness of the coating film (4) After spraying, the objects and articles need to be heated and solidified The curing conditions shall be subject to the technical specifications of the powder products, but the curing temperature and time must be fully guaranteed to avoid quality accidents caused by insufficient curing (5) if defects are found, they shall be dealt with in time If defects are found after curing, the scope of defects is small, but only local The surface decoration of the sound coating can be repaired after diluting with the same color powder and acetone If the scope is large and the surface quality is affected, sandpaper shall be used to polish and spray again or paint remover shall be used to remove the coating and spray again (6) the recycled powder shall be screened to remove the sundries and mixed with the new powder in a certain proportion (7) The powder room and recovery system of the powder supply bucket should avoid the pollution of other powder of different colors, so each color change must be cleaned 2 The construction of art powder spraying requires that the art powder has the characteristics of good appearance, strong stereoscopic sense, good decorative effect, etc., but the construction process is strictly required (1) the input air pressure should not be too large during powder spraying, generally controlled at 0.5-15 kg / cm2 In order to improve the air pressure, it is not advisable to control the voltage around 60-70kv too high, which will lead to the rebound of the powder attached to the surface of the workpiece and other defects (2) when spraying the powder, attention should be paid to ensure that the thickness of the film is generally controlled between 70-100m, which is conducive to the formation of obvious flowers If the coating is thin, the pattern is not obvious and the pattern is small, and there will be defects such as pitting and exposed bottom (3) when curing, it must be baked according to the specified temperature and time If the temperature is too low and the time is too short, the powder will not form a pattern, and the mechanical properties will be greatly reduced due to incomplete curing In addition, due to the special production process of art pattern powder The pattern of recycled powder for sexual use will be smaller or less obvious after re spraying, so it is generally recommended that recycled powder for fine art powder should not be used but also be tested From the above, although the construction requirements are strict, it is believed that as long as the above factors are well grasped in the coating process, the storage and use of powder coating will achieve the desired satisfactory effect 1 Keep away from the fire source and avoid direct sunlight Keep away from the place with good ventilation and temperature below 35 2 Avoid being stored in the place easily polluted by water, organic solvent oil and other materials 3 Do not expose the powder coating to the air at will Cover or turn the bag tightly at any time 4 Avoid the long-term contact of the skin The powder attached to the skin should be washed with soap water Do not use solvent Safety of the coating construction site 1 The equipment used in the coating operation shall be well grounded to eliminate static electricity 2 Avoid the phenomenon of no end discharge of the coating machine 3 Try to control the concentration of the floating dust in the powder spraying room below the safe concentration to avoid the risk of dust ignition and explosion“